Fig. 4

Principle of charge transfer and redistribution through graphene layer. a Schematics of charge transfer through p_z orbitals of graphene layer affected by substrate net charge. The amount of net electron charge was relatively denoted by blue–green–red color column for electron deficiency, neutral, and electron accumulation state in colors ordered. b Atomic model, electron charge density mapping, and charge density difference plot as a function of z-distance at 1L graphene/c-Al₂O₃ system. c Atomic structure and electron charge density maps on 1L graphene/c-Al₂O₃ system